1. Field of the Invention
The field of this invention relates to collapsible dispensing devices suitable for the dispensing of non-solid, viscous material.
2. Description of the Related Art
Cartridges for storing and dispensing viscous materials such as resins, sealing compositions, dental compositions, or insulation compositions are known in the art. Such cartridges generally comprise an outer casing containing at one end, an end piece which attaches to an applicator nozzle and at the other end, a rear thrust wall designed to slide toward the end piece and force the viscous material out of the nozzle. This sliding of the rear thrust wall is brought about by a piston which is generally an integral part of a manually operated device, usually in the form of a gun equipped with a rack or friction advance mechanism.
Some viscous products consist of several viscous components which must be mixed, in given proportions, only at the time of application. It is known in the art to store the viscous components in multiple containers inside cartridges in such a way that the advancing rear thrust wall will force the components through a single mixing nozzle whereby the components become mixed at the time of application.
U.S. Pat. No. 5,339,992 to Barthomeuf et al discloses a cartridge comprising an outer casing and an inner casing. Each casing holds a viscous component of a final product. The cartridge has a front end piece for receiving an application nozzle and a rear thrust wall which drives the components forward and through the nozzle when it is advanced.
U.S. Pat. Nos. 5,161,715, 5,184,757, and 5,242,082 to Giannuzzi disclose a double-barreled gun designed to inject a two-component epoxy composition. The gun contains two parallel barrels, each containing a foil pack containing viscous components of the final epoxy composition. The gun contains two front end pieces which are adapted to send the components into a mixing nozzle. The gun contains two pistons for urging the foil packs forward. As the foil packs are urged forward, cutting elements in the forward end of each barrel slit the foil packs and allow for the discharge of the stored components.
U.S. Pat. No. 5,722,829 to Wilcox et al. and U.S. Pat. No. 5,875,928 to Mxc3xcller et al are similar to each other in that each of these references discloses a double-barreled cartridge capable of receiving two parallel containers containing viscous components which should be mixed only at the time of application. Each container empties into a front end piece which passes the viscous components to a mixing nozzle. Each container has a rear thrust wall which may be forced forward to expel the contents of the container into the front end piece.
U.S. Pat. No. 4,340,154 to VanManen discloses a dispensing container for viscous components wherein the dispenser contains a cartridge containing an accordion-type container. The container holds a first viscous component and the area between the container and the cartridge wall holds a second viscous material. Forward movement of the rear thrust wall pushes both viscous components through a common outlet opening.
While the above dispensing devices are in common use, these devices display qualities which require improvements. One problem is the difficulty of obtaining a range of ratios of the several components. Different end compositions require different ratios of the components. Many dispensers are capable of dispensing only a single ratio of the components. If a different ratio is required, a different type of dispenser must be obtained. Another problem exists with the degree of emptying of the several components. Not all of the above devices afford complete dispensing of the contained components. This leads to wasted materials and the possibility of disposal problems.
The inventor recognized the above problems and solved them by providing a dispenser which comprises a cartridge which fits common caulking guns and a container within the cartridge which may easily be obtained in a variety of sizes and which will provide for complete emptying of the ingredients. Additionally, more than one container may be used for those times when a composition comprising three or more components is to be produced.
The dispenser of the present invention comprises a dispensing cartridge for use with viscous materials which should not be combined until the time of application. The cartridge fits common dispensing guns, such as caulking guns. The cartridge has a front end piece for receiving a dispensing nozzle and a rear thrust wall which drives the contents forward when pushed by the piston of the dispensing gun. Within the cartridge, there is at least one telescopic container holding one of the viscous components. The telescopic containers may be easily produced in a variety of sizes, thus providing a ready availability of a range of ratios of the components. Also the telescopic containers allow for complete emptying of the contained components.